Work is proposed on the analysis of the patterns of macromolecular biosynthesis in cells infected with reovirus and RNA tumor viruses, and on the mode of induction and mode of action of interferon. Among the projects to be investigated are: studies on the translation of the individual reovirus RNA molecules in vitro protein synthesizing systems and characterization of the resultant polypeptides by tryptic peptide mapping; assessment of the significance of an 11th segment of double-stranded RNA present in a ts mutant of reovirus; sequencing of the ribosome-binding sites of the ten species of reovirus messenger RNA molecules; an investigation of the induction of interferon by UV-irradiated reovirus; attempts to purify interferon mRNA by isolating complementary DNA transcribed from it; the development of techniques for the induction of large amounts of interferon in human cells; studies on the mode of action of interferon in inhibiting the multiplication of RNA tumor viruses; examination of the cell-multiplication-inhibitory activity of interferon, particularly against tumor cells; studies of the effect of phosphorylation/dephosphorylation on the activity of B77 DNA polymerase; examination of a highly phosphorylated polypeptide that appears to be strongly associated with B77 DNA polymerase; studies on the characterization of the precursor PR180 in chick embryo fibroblasts infected with B77 which, according to immunological evidence, contains both gag polypeptides as well as the beta polypeptide of the DNA polymerase; and an investigation of the presence and distribution in the plasma membrane of transformed cells of virus-coded antigens and lectin-binding sites.